Expression of S and pre s2 Hepatitis B Surface Antigens in Mammalian Cos-7 Cell Line

Hepatitis B virus (HBV) is a serious global health problem. The development of a safe and effective vaccinewould help infection prevention. Previous hepatitis B vaccine production involved the isolation of the noninfectious particle from chronic HBV carriers. DNA recombinant technology has been used for vaccineproduction without having been contaminated with blood-born infectious agents. Vaccine production inmammalian cells has the advantage of being correctly modified and folded in comparison to other lowerhosts. The surface protein coding genes, S (Major protein) and pre s2+s (Middle protein) of hepatitis B virus(HBV), were amplified from the mother plasmid containing the adr serotype virus genome. The s and pres2+s amplicons were separately cloned in pBlueskript IIks(+) vector as pNM-sa2 and pNM-Psa2 intermediatesrespectively, then released and recloned in pcDNA3 mammalian expression vector. The correct pNM-Sb2and pNM-Psb2 constructs containing s and pre-s2, respectively, were used to transfect the mammalianCos-7 cell line. The major and middle proteins were secreted by this cell line and collected from the culturemedium. Some features of gene cloning strategy and expression of these proteins are discussed.